1. Field of Use
This invention relates generally to suspension means for a vehicle seat, such as a tractor seat or the like, to cushion the ride for the seat occupant by damping vertical motion of the seat and absorbing shocks as the vehicle travels over rough terrain.
2. Description of the Prior Art
Various types of suspension means for resiliently supporting a vehicle seat on some portion of the vehicle, such as the vehicle frame, are known and in use to enable the vehicle seat to move relative to the vehicle frame and thereby cushion the ride for the seat occupant. Prior art seat suspension means or mechanisms typically comprise one or more heavy duty compression springs and other related components which are mounted between the vehicle seat and the vehicle frame and are located directly beneath the seat. Such an arrangement wherein the springs and related components are located beneath the seat prevent the seat from being adjustably positioned as near to the vehicle floor as may sometimes be required to suit the needs of the seat occupant. Furthermore, in some prior art arrangements a severe jolt may cause the seat to descent so far that it runs out of spring travel and comes to an abrupt and jolting stop. Heretofore, it was necessary to mount a resilient block made of rubber or the like beneath the seat and against which the seat could bounce when there was no more spring travel available to cushion the descent. U.S. Pat. No. 4,186,963 to Koutsky entitled "Upright Vehicle Seat Support" discloses supports, for vehicle seats, having a generally upright configuration and having a plurality of seat adjustments. A housing member (13) has facing traces (17), and a carriage member (14) bears the seat and a plurality of rollers (51, 53) which engage the traces (17). A bracket assembly (15), disposed between housing and carriage members (13, 14), is selectively slidable with respect to the carriage member (14) to effect height adjustment and, when locked with respect to the carriage member (14), is operable to effect weight adjustment.
French Pat. No. 929,542 to Rometti discloses springs of different sized serially arranged in a cylinder and upon which a piston acts to effect compressibility, with the smaller springs appearing to compress before the larger springs.